Semi-automatic apparatus for expanding a pressure welded passageway panel



A P. R. STAPLES SEMI-AUTOMATIC APPARATUS FOR EXPANDING A PRESSURE WELDEDPASSAGEWAY PANEL Filed Dec. 9, 1955 Dec. 30, 1958 3 3 \3 m 1 1 L I T i 1ElllllL r r IN VEN TOR. PAUL R. STAPLES BY E ATTORNEY panded into theholding chamber.

United SEMI-AUTOMATIC APPARATUS FOR EXPANDING A PRESSURE WELDEDPASSAGEWAY PANEL 'Paul R. Staples, Louisville, Ky., assignorto ReynoidsMetals Company, Louisville, Ky., a corporation of Delaware Thisinvention relates to a semi-automatic apparatus for expanding theunbonded portions of a pressure welded passageway panel.

It has been proposed to expand a pressure welded or roll bondedpassageway panel on one outer face only by applying a holding liquidunder pressure to that one outer face so to hold its other outer face infiat face-to-face contact with the die and then introducing an expansionliquid under relatively higher pressure into the panel. The holdingpressure on the one outer face of the panel holds the other outer facein relatively unyielding engagement with the die and thus tends toprevent the said other face from expanding while permitting the said oneface to expand into the holding liquid.

Variations occur in the expanding operation when it is controlledmanually. Such variations result in expanded passageways of varyingvolumetric capacity. This is objectionable particularly when theexpanded panel is to be used as an evaporator in a refrigerator ofthetype wherein a capillary tube is employed to provide a pressuredifferential. Here the relationship, between the volume of therefrigerant charge and that of the system, is somewhat critical.

It is an object of the present invention to provide a control apparatusfor developing and applying pressures of the desired magnitude and inthe desired sequence for producing one side expansion of the unbondedpassageway forming'portions of the panel and for automatically releasingthe pressures at the desired rates and times.

Another object is the provision of an apparatus for producing a uniformdegree of expansion throughout the panel so as to minimize volumetricvariations in the expanded passageways due to variations in the overallthickness of the panel.

'A conventional apparatus, for expanding the unbonded portions of apressure welded passageway panel on one side of the panel, comprises: apair of dies relatively movable between open and closed positions, saiddies being adapted to receive a panel in the die open position and tolimit the outward expansion thereof in the die closed position, one ofthe dies having a holding chamber over which said one side of the panelis placed; a hydraulic jack for moving one of said dies; and threeconduits including a die conduit connected to the jack for transmittingdie closing liquid thereto, a holding conduit connecting to the holdingchamber for transmitting panel holding liquid thereto and a panelexpansion conduit adapted for connection to a panel for transmittingpanel expanding liquid to its unbonded portions; and manually operablemeans for supplying liquid under pressure to each of these conduits. Inthe closed position of the dies, the holding chamber is covered by theone adjacent face of a panel interposed between dies. This holdingchamber is large enough lengthwise and widthwise to embrace said oneface over the expansion area containing the unbonded portions of thepanel which are subsequently to be ex- That chamber is also dimensioneddepthwise to limit subsequent expansion to 2,866,429 Patented Dec. 30,1958 ply of holding liquid under pressure, of the holding liquid toinstitute the supply of expansion liquid under pressure and of theexpansion liquid to release all pressures. In the preferred embodiment,the control apparatus comprises: means operating, when manuallyactuated, to supply die closing liquid under pressure to the dieconduit; means operating, when automatically actuated in response to apredetermined pressure in a die conduit, to supply panel holding liquidunder pressure to said holding conduit; means operating, whenautomatically actuated in response to a predetermined pressure in theholding conduit, to supply panel expanding liquid under pressure to saidexpansion conduit; and means operating, when automatically actuated inresponse to a predetermined pressure in the expansion conduit, torelease the pressure in all conduits.

An embodiment of the invention is illustrated in the drawings, wherein:

Figure l is a partly broken plan view of an unexpanded roll bondedpassageway panel;

Figure 2 is a section taken along line HIl of Figure l; and

Figure 3 is a more or less schematic or diagrammatic view of the die andcontrol apparatuses for practicing the present invention.

The present invention can be readily explained in connection with thedrawing which illustrates: a panel; a die apparatus; and a controlapparatus.

PANEL DIE APPARATUS The die apparatus comprises: an upper stationary diemember 5 having a rigid fiat die face 6; a lower movable die member 7'having a die face 8 which is recessed at 9 to provide a holding chamber9 and recessed at 10 to provide an entrance to that holding chamber; an0 sealing ring 11 encircling chamber 9; and a conventional hydraulicjack 12 composed of a piston, also designated 12, and a cylinder 13having a liquid pressure or jack chamber 14.

It will be understood that panel 1 is placed between the upper and lowerdie members 5 and 7 with its bottorn face resting on the O sealing ring11. The dies are closed to effect a very tight seal, between the panel 1and the sealing ring 11, which completes the enclosure of the holdingchamber 9. Now a holding pressure may be introduced into the recess orchamber 9 while an expansion pressure is introduced into the panel I.The control apparatus operates'to eflFect the closing of the dies, theapplication of the holding and expansion pressures and the final releaseof all such pressures.

3 CONTROL APPARATUS The control apparatus comprises: die closing means;panel holding pressure applying means; panel expansion pressure applyingmeans; and pressure releasing means.

Die closing means The die closing means includes a reservoir 16, fromwhich a continuously operating pump 17 draws liquid and pumps it intoconduit 18 which is not only connected to the hydraulic jack chamber 14but also cnnected back to reservoir 16 through a normally open solenoidvalve 19. So long as this valve 19 remains open, it prevents the pump 17from building up a die operating pressure in the jack chamber 14.

The normally open valve 19 is controlled by :1 normally de-energizedsolenoid coil 20. The energization of solenoid coil 20 is controlled bya normally open manually .closable starting circuit which extends fromone side 22 of the supply line through a push button 23, relay coil 24to the other side 25 of the power supply line. The energization of relaycoil 24 closes both ofits normally open switches 26 and.27, switch 26operating to close the solenoid coil 20 circuit extending from line 22through switch 26, coil 20 to line 25 and switch 27 operating toestablish a shunt circuit around push button 23 so as to maintain coil24 energized when push button 23 is released.

With the energization of solenoid coil 20, valve 19 closes the hydraulicreturn circuit from conduit 18 back to the reservoir 16 and thus enablespump 17 to build up a pressure in the hydraulic jack chamber 14sutficient to move the dies to the closed position. When the dies reachthe closed position, the pump 17 will increase the hydraulic pressure onthe dies to a predetermined value, which is determined by the setting ofa normally closed relief valve 28 connecting the conduit 18 back to thereservoir 16. The die holding pressure, at which the dies are heldclosed, or the strength of other means by which they may be held closed,is large enough to overcome the combined effects of the panel holdingpressure, which is to be introduced into the holding chamber 9 of thelower die, and expansion pressure, which is to be introduced into thepressure welded panel 1 itself.

The closure of the dies is usedto initiate the operation of the meansfor applying the holding pressure.

Panel holding pressure applying means Liquid, for panel holding pressurepurposes, is supplied through water supply 30, check valve 31, conduit32, normally closed solenoid valve 33 and conduit 34 to the holdingchamber 9. T 0 open the normally closed panel holding pressure line 34,the coil for solenoid valve 33 must be energized. The means to energizeit is made responsive to the closure of the dies by connecting sole noidcoil 55 to the power supply line through a normally open switch 37 whichis responsive to the die holding pressure in the jack chamber 14 and theconduitlS and which is designed to close when the pressure, developed incircuit 18, rises to a value suflicient to prevent the dies from beingforced apart during the expansion operation by the maximum counteractingload imposed on the piston as a result of the expansion operation.

To provide a panel holding fluid, under the requisite value of holdingpressure, a compressed air supply .40 is connected, through solenoidvalve 41, to the low pressure side of a booster accumulator 42, the highpressure side of which is connected to the holding liquid conduit 32.The booster accumulator 42 is of conventional structure utilizing a lowair pressure acting on the large area of a differential piston to apply,to the liquid in the hydraulic conduit 32, a large total pressurethrough the smaller differential area ofthat same piston. The boosteraccumulator 42 .is made to operate, in response to the closure of thedies, by connecting its solenoid coil 43 and the solenoid coil 35 forthe valve 33, in parallel between line 22 on the one side and switch 37on the other.

Now it will be understood that, when the die holding pressure in conduit18 reaches its predetermined die holding value, it becomes effective toclose pressure switch 37, which is .in series with each of the parallelsolenoid coils 35 and .43. As a result, the panel holding pressure line34, leading to the holding chamber 9, is opened and the boosteraccumulator 42 operated to place the liquid line 34 and chamber 9 undera panel holding pres sure of a predetermined order.

The rise of the panel holding pressure, toward or to a predeterminedvalue, is used to imitate the operation of the means for applying theexpansion pressure.

Panel expansion pressure applying means The panel expansion pressureliquid system includes water supply 30 leading through check valve 31and conduit 47 to a quickly detachable coupling 48 for the fluidpressure connector 4. The coupling 48, for connector 4, is of theconventional quick-operating type having a valve, which, when thecoupling is connected, provides an open passageway between expansionliquid conduit 47 and the interior of the fluid connector 4, and, whenthe coupling is disconnected, closes the end of the conduit 47 and thusprevents the leakage of water.

The panel expansion system is made responsive, to a predetermined valueof panel holding pressure in the conduit 34 and holding chamber 9, byconnecting the compressed air supply 40 through solenoid valve 51 to abooster accumulator 52 and by connecting the coil 53 of the solenoidvalve 51 to power through a normally open pressure switch 54 which isresponsive to the panel holding pressure in conduit 34. The circuit forsolenoid coil 53 extends from one side 22 of the line through solenoidcoil 53, pressure switch 54 and pressure switch 37 to the other side ofthe line 25. As a consequence, as soon as coil 53 is energized, thebooster accumulator 52 operates to impose an expansion pressure in thehydraulic expansion circuit containing conduit 47 causing the panell tobe expanded as the expansion pressure in its passageway system rises toa predetermined value.

The top value of expansion pressure, which is predetermined, is used toinitiate the operation of the means for releasing all pressures.

Pressure release means When the expansion pressure reaches apredetermined value, it is desirable to release the pressure and shutdown the entire apparatus. Accordingly, a normally closed pressureswitch 60, which is responsive to the expansion pressure, is arranged toopen at the predetermined top expansion pressure. This switch 60 isserially connected with relay switch 27 to form the shunt circuit, whichextends around push button switch 23 and which maintains therelay-energizing circuit of relay coil 24 closed when switch 23 opens.Consequently, when switch 60 is opened, it de-energizes relay coil 24causing relay switches 26 and 27 to open.

The opening of relay switch 26 de-energizes the solenoid coil 20 to openvalve 19. This releases the pressure in the hydraulic die-holdingcircuit, allowing the dies 5 and 7 to open. The release of thedie-holding pressure, opens pressure switch 37, which, in turn, openstwo electric circuits, namely: the electric circuit of solenoid coils 35and 43 respectively, controlling the fiow of panel holding fluid in thehydraulic holding circuit through valve 33 and the application ofpressure thereto through valve 41; and the electric circuit of solenoidcoil 55, controlling the application of pressure to the panel expandingfiuid in the hydraulic expansion circuit through valve 51. As a result,the panel holding and expanding pressures are immediately released.

The opening of relay switch 27 creates a second opening in the shuntcircuit around push button 23, and thus prevents relay coil 24 fromimmediately becoming reenergized by the re-closure of pressure switch60, which re-closure occurs with the release of expansion pressure inline 47.

The de-energization of the relay coil 24 and the opening of its switches26 and 27 thus conditions the apparatus for the next series ofoperations involving the removal of the expanded panel, its replacementby the next unexpanded panel and the institution of the automaticoperations which follow the closure of the manually 0perated push button23.

Operating conditions and variations The fluid pressure valves used will,of course, vary depending on the composition of the panel. With aconventional aluminum panel, a differential between the holding andexpansion pressures of about 2,000 to 3,000 p. s. i. is recommended.With a differential of 2,400 p. s. i., a holding pressure of 600 p. s.i. and an expansion pressure of 3,000 p. s. i. may give good result butprogressively higher holding pressures, Within operating limits, shouldgive progressively better results. Necessarily, whatever the holding andexpansion pressures are, the pressure which holds the dies closed mustbe sufficient to resist the die separating forces created by the holdingand expansion pressures.

The present invention may be applied to a die apparatus for expandingboth sides by eliminating the holding chamber, holding conduit and theholding'liquid pressure supply means and by making the expansion liquidpressure supply means automatically responsive to the die closingpressure. The latter can be accomplished swiftly by eliminating pressureswitch 54 and permanently closing the contacts of switch 54.

I claim as my invention:

An apparatus for expanding certain unbonded portions of a pressurewelded passageway panel on one side or face of the panel comprising: apair of dies relatively movable between open and closed positions, saiddies being adapted to receive a panel in the open position and to limitthe outward expansion thereof in the closed position, one of said dieshaving a holding chamber which, in the closed position of the dies, iscovered by the one adjacent face of an interposed panel, said holdingchamber being large enough lengthwise and widthwise to embrace said oneface over the expansion area containing said unbonded portions which aresubsequently to be expanded into the holding chamber and beingdimensioned depthwise to limit the expansion to a predetermined extentwhereby variations between the unbonded portions of the panel faces maybe accommodated, the other die having flush face-to-face engagement withthe other face of said panel over an area corresponding to saidexpansion area; a hydraulic jack for moving one of said dies; a dieconduit connected to the jack for transmitting die closing liqudthereto; a holding conduit connected to the holding chamber fortransmitting panel holding liquid thereto; an expansion conduit adaptedfor connection to a panel for transmitting panel expanding liquid to itsunbonded portions; means operating, when manually actuated, to supplydie closing liquid under pressure to the die conduit; means operating,when automatically actuated in response to a predetermined dieclosingliquid pressure, to supply panel holding liquid to said ho-ldingchamberthrough said holding conduit under a predetermined holding pressureexerted against said one face for the purpose of maintaining saidcorresponding area of said other face in flush face-to-face engagementwith said other die during subsequent expansion; means operating, whenautomatically actuated in response to a predetermined panel-holdingliquid pressure, to supply panel expanding liquid to the interior ofsaid panel through said expansion conduit under a predeterminedpanel-expanding liquid pressure suflicient to expand said unbondedportions on said one face into said holding chamber against said holdingpressure therein but insufficient to expand the corresponding unbondedportions on said other panel face while such portions are held in saidflush engagement with said other die by said holding pressure; and meansoperating, when automatically actuated in response to a predeterminedpanel-expanding liquid pressure, to release said die-closing,panelholding and panel-expanding pressures.

References Cited in the file of this patent UNITED STATES PATENTS1,891,121 Thoreson Dec. 13, 1932 2,241,807 Cotner May 13, 1941 2,317,869Walton Apr. 27, 1943 2,398,227 Hubbert Apr. 9, 1946 2,582,358Schoellerman Jan. 15, 1952 2,625,195 Tremblay Jan. 13, 1953 2,690,002Grenell Sept. 28, 1954 2,713,314 Leuthesser et a1. July 19, 19552,766,711 Dever et a1. Oct. 16, 1956

